Driver for operating multiple display devices

ABSTRACT

A driver chip for controlling a high-resolution display panel is presented. The driver chip is not much larger than a conventional driver chip that is currently used for lower resolution display panels. The driver chip applies data signals to the data lines of the display panel and gate control signals to a gate driver that is formed in the peripheral region of the display panel. The gate driver, which may be made of amorphous silicon TFTs, generates gate signals in response to the gate control signals from the driver chip and applies the gate signals to gate lines. Since the driver chip of the invention controls more gate lines and data lines than a conventional chip of about the same size, the driver chip may be easily adapted for display devices having multiple panels. Where multiple panels are used, the panels may be scanned simultaneously or sequentially.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.10/873,607, filed Jun. 21, 2004 now U.S. Pat. No. 7,385,598, and claimspriority, under 35 USC §119, from Korean Patent Application No.2003-42356filed on Jun. 27, 2003 and Korean Patent Application No.2003-70190 filed on Oct. 9, 2003, the contents of which are incorporatedherein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a flat panel display device, and moreparticularly to a flat panel display device with high resolution.

2. Description of the Related Art

As wireless phones gained popularity over the past several years, manydifferent models of wireless phones have come into existence. One of thepopular models is a folding phone, commonly referred to as a “flipphone.” A typical flip phone is made of a display module, a controlmodule, and a hinge mechanism for connecting the two modules such thatthey can be folded into a compact form when the phone is not in use. Thedisplay module is used primarily for conveying information to users, andthe control panel is used for receiving user input.

Flip phones often come in a dual-panel configuration, whereby thedisplay module includes multiple liquid crystal display (LCD) panels.Sometimes, the display module is made with two LCD panels: a primary LCDpanel that is visible only when the phone is open (or unfolded), and asecondary LCD panel that remains exposed even when the phone is folded.The secondary LCD panel is typically smaller than the primary LCD paneland displays limited information. Usually, the secondary panel displaysinformation that users would want to see without unfolding the phone(e.g., time, message alert).

Generally, the primary LCD and the secondary LCD each has its own driverchip, resulting at least two separate chips per phone. This use of twoor more different chips is economically disadvantageous, both from acircuit design perspective and a manufacturing cost perspective. Toreduce this economic inefficiency, much research effort has been gearedto designing a chip that can drive both LCD panels.

FIG. 16 is a partial view of a currently existing driver chip 50 that isdesigned to control multiple display panels. The Figure shows 12 contactpads 60 (herein also referred to as “terminals”) arranged along a firstedge 52 of the driver chip 50 and eight contact pads 60 arranged along asecond edge 54 of the driver chip 50. The contact pads 60 arecategorizable into three groups: the data signal contact pads 62, thefirst gate signal contact pads 64, and the second gate signal contactpads 66. As is well known, the number of contact pads determines theresolution of the display panel; hence, the more contact pads there are,the higher the resolution. Although it is desirable to increase theresolution of the display panel by increasing the number of contactpads, increasing the number of contact pads is undesirable because itleads to a larger driver chip 50 and therefore a larger device. Sincethe contact pads are spaced apart by a minimum distance to achieve adesired level of reliability and quality, it is equally undesirable totry to increase the number of contact pads without increasing the sizeof the driver chip 50. Due to these limitations, the currently availabledriver chip 50 is only usable with low-resolution displays.

A driver chip that can control multiple display panels including atleast one high-resolution display without the attendant increase in chipsize is desired.

SUMMARY

The invention provides a way to produce a high-resolution display devicewithout significant increase in driver chip size. In one aspect, theinvention is electronic device that includes a display area having aplurality of gate lines and a plurality of data lines, a peripheralregion surrounding the display area, a gate driver formed in theperipheral region, wherein the first gate driver provides gate signalsto the gate lines, and a driver chip spaced apart from the gate driver.The driver chip generates a plurality of gate control signals for thegate driver. In addition, the driver chip generates data signals for thedata lines.

In another aspect, the invention is a driver chip set for use with anelectronic device having a display panel. The chip set includes anintegrated circuit chip and a gate driver that is outside the integratedcircuit chip. The integrated circuit chip has an input terminal forreceiving an input data signal and an input control signal, a controlsection coupled to the input terminal for converting the input datasignal to data signals and converting the input control signal to gatecontrol signals, a plurality of data signal output terminals coupled tothe control section for transmitting the data signals. As for the gatedriver, it applies gate signals to gate lines in response to the gatecontrol signals from the driver chip.

The invention further includes a display panel driver chip having arectangular surface, wherein the chip receives input signals from a CPUand outputs signals to data lines, a first set of gate lines for thefirst display panel, and a second set of gate lines for the seconddisplay panel.

In yet another aspect, the invention includes specific arrangements ofinput terminals and output terminals on the rectangular surface of thedriver chip to accommodate the data lines and gate lines of ahigh-resolution display panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary electronic device includingmultiple display panels;

FIG. 2 is a block diagram of the control configuration for theelectronic device of FIG. 1;

FIG. 3 is a schematic view of an electronic device including a firstembodiment of the invention;

FIG. 4 is a block diagram of the driver of FIG. 3;

FIG. 5 is a schematic diagram of an electronic device including a secondembodiment of the invention;

FIG. 6A is a schematic diagram of the first gate driver that may be usedwith the embodiment of FIG. 5;

FIG. 6B is a circuit diagram illustrating one implementation of thefirst gate driver of FIG. 6A;

FIG. 7 is a block diagram of the driver of FIG. 5;

FIG. 8A and FIG. 8B are enlarged views of the driver of FIG. 5;

FIG. 9 is a schematic diagram of an electronic device including a thirdembodiment of the invention;

FIG. 10 is a schematic diagram of the second gate driver that may beused with the embodiment of FIG. 9;

FIG. 11 is a block diagram of the driver of FIG. 9;

FIG. 12A and FIG. 12B are enlarged views of the driver of FIG. 9;

FIG. 13 is a schematic diagram of an electronic device including afourth embodiment of the invention;

FIG. 14 is a block diagram of the driver of FIG. 13;

FIG. 15A and FIG. 15B are enlarged views of the driver of FIG. 13; and

FIG. 16 is a currently available driver for operating multiple displaypanels.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention are described herein in the context ofdisplay devices and more specifically in the context ofdual-display-panel wireless phones. However, it is to be understood thatthe embodiments provided herein are just preferred embodiments, and thescope of the invention is not limited to the applications or theembodiments disclosed herein. For example, the invention may be adaptedto any device or usage including at least one display panel.

Conventional driver chips include input terminals for receiving signalsfrom a CPU and output pads for driving the gate lines and the data lines(control signals, data signals, and gate line voltages). As the displayresolution gets higher, the number of gate lines and data lines alsoincrease, requiring more terminals on the driver chip. Due to the limiton the number of terminals that can fit into a given-sized chip, thechip size limit is essentially a limit on the display panel resolution.

The driver chip of the invention controls high-resolution display panelswithout the usually-attendant increase in size. The chip driver of theoperates a greater number of gate lines and data lines by transferringsome of the gate driving function to a gate driver formed in theperipheral region of the display panel, for example in the form of flipflops. The driver chip of the invention sends clock signals (CK, CKB)and start signals (ST) to the gate driver but do not apply gate signalsto the gate lines. By limiting the gate driving function of the chipdriver this way, fewer terminals are needed for gate driving, and chipreal estate is freed up to be used for more data lines. Source andground voltages are fed to the gate driver separately from the gatecontrol signals.

The gate driver in the peripheral region of the display device may bebuilt with amorphous silicon thin film transistors for integration intothe display panel. Further details about amorphous silicon thin filmtransistor LCD devices are disclosed in U.S. Publication No.2003/0222311 published on Dec. 4, 2003, which is incorporated herein byreference in its entirety.

FIG. 1 is a perspective view of an exemplary electronic device 600including a display module 100 connected to a control module 400. Theelectronic device 600 is powered by a battery 500. The display module100, which displays information, includes a primary display panel 200and a secondary display panel 300. As mentioned above, the primarydisplay panel 200 is usually only viewable when the electronic device600 is open, or unfolded, as shown in FIG. 1. The secondary displaypanel 300, on the other hand, is viewable even when the phone is closedor folded. The battery 500 is detachably attached to the control module400, and may be any form of power supply device.

The control module 400 has keys 410 that a user can use to inputinformation. The control module 400 generates signals in response touser input and provides the signals to the primary display panel 200.The primary display panel 200 displays images that reflect the userinput.

Typically, the primary display panel 200 displays main information andthe secondary display panel 300 displays only stand-by information suchas time and date. “Stand-by information” is information that isdisplayed independently of user input. Due to this different usage ofthe two panels, the primary display panel 200 is larger than thesecondary display panel 300 and has a higher resolution. For example,the resolution of the primary display panel 200 may be 128×160 and theresolution of the secondary panel may be 96×64.

FIG. 2 is a block diagram of the control configuration of the electronicdevice 600 according to an exemplary embodiment of the presentinvention. In more detail, the electronic device 600 includes theprimary display panel 200, the secondary display panel 300, and a driver230 for driving the two panels 200, 300. The driver 230 receives anoriginal data signal O-DATA and an original control signal OCS from aCPU 100. The original data signal O-DATA includes data signals forcolors red (R), green (G), and blue (B). The original control signal OCSincludes a vertical synchronous signal Vsync, a horizontal synchronoussignal Hsync, and a main clock signal MCLK.

The driver 230 outputs various signals for driving the primary andsecondary panels 200, 300, in response to the original data signalO-DATA and the control signals OCS. In more detail, the driver 230converts the original data signal O-DATA and the original control signalOCS to a first data signal M-DATA, a second data signal S-DATA, firstand second vertical control signals VCS1 and VCS2, and first and secondcommon voltages Vcom1 and Vcom2. These signals are selectively forwardedto the primary display panel 200 and the secondary display panel 300.

As shown, the primary display panel 200 receives the first and seconddata signals M-DATA and S-DATA from the driver 230. The primary displaypanel 200 also receives the first and the second vertical controlsignals from the driver 230. While the primary display panel 200displays information according to the first data signals M-DATA, ittransfers the second data signals S-DATA to the secondary display panel300 without displaying them as images. The secondary display panel 300displays the images that correspond to the second data signals S-DATA.

Similarly, the primary display panel 200 filters out the first verticalcontrol signal VCS1 and the first common voltage Vcom1, passing only thesecond vertical control signal VCS2 and the second common voltage Vcom2to the secondary display panel 300. Thus, the secondary display panel300 receives only the data that is intended for it.

A first gate driver (indicated with reference numeral 240 in FIGS. 3, 5,9, and 13 below) is formed on the primary display panel 200, and asecond gate driver (indicated with reference numeral 310 in FIGS. 3, 7,9, and 13 below) may be formed on the secondary display panel 300. Thefirst gate driver 240 receives the first gate control signal (VCS1) fromthe driver chip 230 and outputs a first gate signal in response to thefirst gate control signal (VCS1). Similarly, the second gate driver 310receives the second gate control signal (VCS2) from the driver chip 230and outputs a second gate signal in response to the second gate controlsignal (VCS2). These first and second gate signals are applied to thegate lines in the first and second display panels 200, 300,respectively. Also, the first and second common voltages Vcom1 and Vcom2output from the driver 230 are applied to the primary and secondarypanels 200, 300, respectively.

The “gate control signal” used herein is sometimes referred to as avertical control signal. A gate control signal includes a start signal(ST), a first clock signal (CK), and a second clock signal (CKB). Thefirst clock signal and the second clock signals are based on the mainclock signals in the input signal OCS. A gate driver generates gatesignals in response to a gate control signal and according to the clocksignals. The “data control signal” used herein is sometimes referred toas the “horizontal control signal,” and control the data lines.

By using the configuration that is illustrated in FIG. 2, the inventionallows the driver chip 230 to drive more gate lines and data lines thana conventional driver chip. The configuration of FIG. 2 also includesone or more gate drivers formed in the peripheral region of the displaypanels. The driver chip 230 controls the gate drivers with gate controlsignals. The driving chip 230 is especially valuable for applicationswhere size is an important feature of the product, such as wirelesselectronic devices, because it is able to operate high-resolutiondisplays without an attendant increase in chip size. For example, thedriver chip 230 having a size comparable to a conventional driver chipcan be used for a wireless phone having a primary display panel 200 witha resolution of 176×220 and a secondary display panel with a resolutionof 96×64 (or 64×96).

Numerous embodiments of the driver 230 are possible, only some of whichwill be illustrated herein. In the interest of clarity, the componentsof the different embodiments will be described with an alphabeticindicator attached to the reference numeral. Four embodiments of thedriver 230 will be referred to as the driver 230 a, 230 b, 230 c, and230 d.

FIG. 3 is a schematic view of the electronic device 600 a. As shown, theprimary display panel 200 a includes a first display area DA₁ surroundedby a first peripheral region. The first peripheral region is made of afirst sub-region SA1, a second sub-region SA2, a third sub-region SA3,and fourth sub-region SA4. The first display area DA₁ is coupled to theCPU 100 (shown in FIG. 2) with a first printed circuit board 250 andcoupled to a second display area DA₂ with a second printed circuit board350 a. The second display area DA₂ is surrounded by a second peripheralregion, which is made of a fifth sub-region SA5 and a sixth sub-regionSA6.

The first display area DA₁ has n first gate lines that are shown in theFigure as GL₁₋₁ to GL_(1−n), and m first data lines that are shown asDL₁₋₁ to D_(1−m). The first gate lines extend in a first direction, andthe first data lines extend in a second direction that is substantiallyperpendicular to the first direction.

The second display area DA₂ has i second gate lines, shown in the Figureas GL₂₋₁ to GL₂₋₁, and j second data lines that are shown as DL₂₋₁ toDL_(2−j). The second gate lines extend in a third direction, and thesecond data lines extend in a fourth direction that is substantiallyperpendicular to the third direction.

The primary display panel 200 a is larger than the secondary displaypanel 300 a, and the first display area DA₁ is larger than the seconddisplay area DA₂. Further, the first display area DA₁ has a higherresolution than the second display area DA₂. Accordingly, the number ofgate lines and data lines generally follow the pattern set forth below:

-   -   n, m, i, j are each a natural number equal to or greater than 2    -   i≦n    -   j≦m

A driver 230 a for driving the primary display panel 200 and thesecondary display panel 300 are mounted on the first sub-region SA1. Thefirst flexible printed circuit board 250, which is electricallyconnected to the driver 230 a, forwards the original data signal O-DATAand the original control signal OCS from the CPU 100 (see FIG. 2) to thedriver 230 a.

A first gate driver 240 a is formed in the first peripheral region. Inthe particular embodiment shown, the first gate driver 240 a is formedin the second sub-region SA2, and is configured to receive signals fromthe driver 230 a and distribute the first gate signals to the first gatelines GL₁₋₁ to GL_(1−n). A second gate driver 310 a is formed in thesecond peripheral region. The second gate driver 310 a, which is formedin the sixth sub-region SA6, is configured to receive signals from thedriver 230 a and distribute the second gate signals to the second gatelines GL₂₋₁ to GL_(2−i).

FIG. 4 is a block diagram of the driver 230 a shown in FIG. 3. As shown,the driver 230 a includes a control section 231 a, a memory section 232a, a data driving section 233 a, a gray scale voltage generating section235 a, and a voltage generating section 236 a. The control section 231 areceives the data signals O-DATA and the original control signal OCSfrom the CPU 100 (see FIG. 2), and provides the received signals to thememory section 232 a. The memory section 232 a stores the original datasignal O-DATA (WRITE DATA). Then, the control section 231 a reads thefirst and second data signals M-DATA and S-DATA from the memory section232 a, line by line, in response to the control signals OCS (READ DATA).

The control section 231 a outputs the first and second data signalsM-DATA and S-DATA read from the memory section 232 a. The controlsection 231 a also outputs a data control signal (HCS) to the datadriving section 233 a, and outputs a first and second gate controlsignals (VCS1 and VCS2) to the gate drivers 240 a and 310 a. Althoughnot shown in FIG. 4, the control section 231 a includes a timing sectionthat generates clock signals CK and CKB. The control section 231 a alsooutputs a gray scale control signal (GCS) to the gray scale voltagegenerating section 235 a.

The gray scale voltage generating section 235 a outputs gray scalevoltage Vg in response to the gray scale control signal GCS providedfrom the control section 232. The data driving section 233 a requiresthe gray scale voltage Vg corresponding to a number of bits of first andsecond data signals M-DATA and S-DATA provided from the control section231 a. For example, when the first data signal M-DATA or the second datasignal S-DATA corresponds to 6 bits, the gray scale voltage generatingsection 235 a generates 64 (=2⁶) gray scale voltages Vg. The datadriving section 233 outputs the first data signal M-DATA or the seconddata signal S-DATA in response to the data control signal (HCS), usingthe gray scale voltage Vg.

The voltage generating section 236 a receives a source voltage Vp froman external device and adjusts the source voltage Vp to output first andsecond common voltages V_(com1) and V_(com2). The common voltagesV_(com1) and V_(com2) are then forwarded to the primary and thesecondary panels 200, 300. The voltage generating section 236 a mayoutput a first driving voltage for driving the control section 231 a, asecond driving voltage for driving the data driving section 233 a, athird driving voltage for driving the first gate driver 240 a, and afourth driving voltage for driving the second gate driver 310 a.

Referring back to FIG. 3, the first gate driver 240 a that is formed inthe second sub-region SA2 of the first peripheral region applies thefirst gate signal to the first gate lines GL₁₋₁ to GL₁₋₁ n in responseto the first vertical control signal VCS1 from the driver 230 a.Similarly, the second gate driver 310 a that is formed in the sixthsub-region SA6 of the second peripheral region applies the second gatesignal to the second gate lines GL₂₋₁ to GL_(2−i), in response to thesecond vertical control signal VCS2 from the driver 230.

A second printed circuit board 350 electrically connects the primarydisplay panel 200 and the secondary display panel 300. A first end ofthe second flexible printed circuit board 350 is attached at the fourthsub-region SA4 of the primary display panel 200, and a second end of thesecond flexible printed circuit board 350 is attached at the fifthsub-region SA5 of the secondary display panel 300. The second flexibleprinted circuit board 350 includes connection lines CL₁₋₁-CL_(1−j) forelectrically connecting DL₁₋₁ to DL_(1−j) (i.e., a subgroup of the firstdata lines DL₁₋₁ to DL1−m) to the second data lines DL₂₋₁ to DL₂₁.

The second flexible printed circuit board 350 keeps the driver 230 aelectrically connected with both the primary and the secondary displaypanels 200, 300 even when the driver chip 230 is directly physicallyattached to only the primary display panel 200. The second data signalS-DATA are transmitted to the second data lines DL₂₋₁ to DL_(2−j) of thesecondary display panel 300 via first data lines DL₁₋₁ to DL_(1−j) andthe connection lines CL₁₋₁ to CL_(1−j). Likewise, the second verticalcontrol signal VCS2 and the second common voltage V_(com2) output fromthe driver 230 a are transmitted to the secondary display panel 300 viathe primary display panel 200 and the second flexible printed circuitboard 350.

The driver 230 a has an input terminal through which it receives theoriginal data signal O-DATA and the original control signal OCS, andthree sets of signal output terminals: a first set of output terminalsfor transmitting the data line signals, a second set of output terminalsfor transmitting the first gate signals, a third set of output terminalsfor transmitting the second gate signals. The driver 230 a also includesvoltage output terminals Vcom1 and Vcom2. Each “set” of output terminalsincludes at least one contact pad located on the chip surface.

As shown, one driver 230 a drives both the primary display panel 200 aand the secondary display panel 300 a in the electronic device 600 a. Bymoving the gate driving circuits out of the driver chip 230, valuablereal estate in the driver chip 230 is freed up for data driving. Sincethe peripheral regions of the display panels were not used for anyelectrical connections, this “wasted space” is utilized by forming thefirst and second gate drivers 240 a and 310 a therein. The overalleffect of moving the gate driving circuits from the driver chip to theperipheral region(s) is the ability to drive high-resolution displaypanels in a space-efficient manner.

Embodiment 1

FIGS. 5, 6, 7, 8A, and 8B pertain to the electronic device 600 includingthe first embodiment of the driver 230, referred to herein as the driver230 b. The same reference numerals are used to indicate components thatare similar to the components that are described above. However, thealphabetic indicator “b” will be attached to the components of thisembodiment for clarity. The gray scale voltage generating section 235and voltage generating section 236 are omitted in FIG. 7 for clarity ofillustration.

The driver 230 b has three output terminals. However, unlike the driver230 a, which had two gate drivers 240 a, 310 a that were locatedexternal to the driver chip 230 a, only a part of the gate driver isexternal to the driver 230 b. The electronic device 600 b has a firstgate driver 240 b that is formed in the first peripheral region and asecond gate driver 234 b that is integrated into the driver 230 b.

FIG. 5 is a schematic view of the primary and secondary display panels200, 300 that are operated by the driver 230 b. As in the embodimentdescribed above, the primary display panel 200 has first gate linesGL₁₋₁ to GL_(1−n) and first data lines DL₁₋₁ to DL_(1-m). The driver 230b receives signals from the CPU 100 (see FIG. 2) via the first printedcircuit board 250 and outputs different data line signals for the firstdata lines DL₁₋₁ to DL_(1−m). As for the gate lines GL₁₋₁ to GL_(1−n),the driver 230 b forwards the gate line signals to the first gate driver240 b, which then distributes the signals to the gate lines GL₁₋₁ toGL_(1−n).

The secondary display panel 300 b is also driven by the driver 230 b. Asubgroup of the first data lines, namely DL₁₋₁ to DL₁₋₁ j, areelectrically coupled to the second data lines DL₂₋₁ to DL_(2−j) via theconnection lines CL₁₋₁ to CL_(1−j) on the second printed circuit board350 b. Signals are transmitted from the driver 230 b to the second gatelines GL₂₋₁ to GL₂₋₁ via a path that runs along the third sub-regionSA3, across the second printed circuit board 350, and along the sixthsub-region SA6. At the sixth sub-region SA6, the signals are distributedamong the second connection lines CL₂₋₁ to CL_(2−j), which respectivelycouple to the second gate lines GL₂₋₁ to GL_(2−i).

FIG. 6A is a schematic diagram of the first gate driver 240 b inaccordance with the first embodiment. The first gate driver 240 b iselectrically connected to the first gate lines GL₁₋₁ to GL_(1−n), andprovides the first gate lines GL₁₋₁ to GL_(1−n) with a first gate signalin sequence. The first gate driver 240 b includes a shift registerhaving (n+1) number of states, SRC₁ to SRC_(n+1), that are electricallyconnected to each other. Each state has an input terminal IN, an outputterminal OUT, and a control terminal CT. An output terminal OUT of astage is electrically connected to the control terminal CT of theprevious stage and an input terminal IN of the succeeding stage.

The first start signal ST1 is applied to the first stage SCR₁. Inaddition to the start signal ST1, the first gate driver 240 b receives afirst clock signal CK1, a second clock signal CKB1, a ground voltage Vssand a source voltage V_(DD). The phase of the second clock signal CKB1is inverse of the phase of the first clock signal CK1.

The odd numbered stages SCR₁, SCR₃, . . . SCR_(n+1) receive the firstclock signal CK₁. The even numbered stages SCR₂, SCR₄, . . . SCR_(n)receive the second clock signal CKB1. When the first start signal ST1 isapplied to the first stage SCR1, the first stage SCR1 outputs the firstclock signal CK1 as a first gate signal. The second stage SCR2, uponreceiving the first gate signal, outputs the second clock signal CKB1 asa second gate signal. FIG. 6B is a circuit diagram illustrating apossible implementation of the first gate driver 240 b.

FIG. 7 is a block diagram of the driver chip 230 b. The driver chip 230b includes a control section 231 b, a memory section 232 b, and a secondgate driver 214 b. In addition, the driver chip 230 b includes a secondgate driver 234 b that is integrated into the driver chip 230 b. Thedriver chip 230 b receives an original data signal O-DATA and anoriginal control signal OCS via an input terminal (IN). The originaldata signal O-DATA includes data for red, green, and blue pixels. Theoriginal control signal OCS includes a vertical synchronization signal,a horizontal synchronization signal, and a main clock.

As mentioned above, the driver 230 b includes three sets of outputterminals: data signal output terminals (OT₁₋₁ to OT_(1−m)), first gatecontrol signal output terminal(s) (OT₂), and second gate control signaloutput terminal(s) (OT₃₋₁ to OT_(3−i)).

The driver 230 b is a rectangular chip having four edge regions: a firstedge region EP₁, a second edge region EP₂, a third edge region EP₃, anda fourth edge region EP₄. The contact pads in each edge region arearranged along the edge that defines the edge region. The edges near thefirst and second edge regions EP₁, EP₂ are parallel to each other, andthe edges near the third and the fourth edge regions EP₃, EP₄ areparallel to each other. As shown, the input terminal IN is located nearthe first edge region EP₁. The data signal output terminals OT₁₋₁ toOT_(1−m) are located near the second edge region EP₂, a first gatesignal output terminal OT₂ is located near the third edge region EP₃,and a second gate signal output terminal OT₃ is located near the fourthedge region EP₄.

The control section 231 b provides the original data signal O-DATA tothe memory section 232 b, which then stores the original data signalO-DATA. As mentioned above, the original data signal O-DATA includes thefirst data signals M-DATA and the second data signals S-DATA. The inputcontrol section 231 b reads the first and second data signals M-DATA anS-DATA stored in the memory section 232 b line by line, in response tothe original control signal OCS, and forwards it to the data drivingsection 233 b. The control section 231 b also outputs the horizontalcontrol signal HCS for controlling the data driving section 233 b, sothat the data driving section 233 b knows when to transmit the first andsecond data signals M-DATA and S-DATA. In addition, the control section231 b outputs the first gate control signal (VCS1) for controlling thefirst gate driver 240 b, and the second gate control signal (VCS2) forcontrolling the second gate driver 234 b.

The data driving section 233 b provides the first data signal M-DATA andthe second data signals S-DATA to a set of data signal output terminalsOT₁₋₁ to OT_(1−m) in response to the data control signal HCS receivedfrom the control section 231 b.

FIG. 8A and FIG. 8B are enlarged views of the portions labeled “A” and“B” in FIG. 5, respectively. As shown in FIG. 8A, a first group of thedata signal output terminals OT¹⁻¹ to OT_(1−m) are disposed at thesecond edge region EP₂, and a second group of the data signal outputterminals are disposed at the third edge region EP₃. As shown in FIGS. 5and 7, the data signal output terminals OT₁₋₁ to OT_(1−m) areelectrically connected to the first data lines DL₁₋₁ to DL_(1−m) at thefirst sub-region SA1. A subgroup of the first data lines DL₁₋₁ toDL_(1−j) is electrically connected to the second data lines DL₂₋₁ toDL_(2−j) via first connection lines CL₁₋₁ to CL_(1−j). In more detail,the first connection lines CL₁₋₁ to CL_(1−j) are electrically connectedto the first data lines DL₁₋₁ to DL_(1−j) at the fourth sub-region SA4,and to the second data lines DL₂₋₁ to DL_(2−j) at the fifth sub-regionSA5.

Thus, the first data signal M-DATA output from the data driving section233 b is applied to the first data lines DL₁₋₁ to DL₁₋₁ m. The seconddata signal S-DATA is applied to the second data lines DL₂₋₁ to DL_(2−j)via the first connection lines CL₁₋₁ to C_(1−j).

As shown in FIG. 8A, the driver chip 230 b further includes first gatecontrol signal output terminals OT₂ for outputting the first gatecontrol signal (VCS1). In the particular embodiment, there is only onefirst gate control signal output terminal. The first gate signal outputterminal OT₂ is disposed at the third edge region EP₃ of the driver chip230 b.

Referring to FIGS. 5 and 7, the second gate control signal outputterminals OT₃₋₁ to OT_(3−i) are electrically connected to the secondconnection lines CL₂₋₁ to CL_(2−i). The second connection lines CL₂₋₁ toCL_(2−i) extend from the second gate control signal output terminalsOT₃₋₁ to OT_(3−i) along the third peripheral portion SA3 and the secondprinted circuit board 350, to eventually couple to the second gate linesGL₂₋₁ to GL_(2−i). Thus, the second gate control signal output from thesecond gate signal output terminals OT₃₋₁ to OT_(3−i) is applied to thesecond gate lines GL₂₋₁ to GL_(2−i) formed on the second display regionDA₂.

In this embodiment, the second gate driver 234 b is built into thedriver 230 b, resulting the same number of second gate signal outputterminals OT₃₋₁ to OT_(3−i) as the number of second gate lines GL₂₋₁ toGL_(2−i). However, because the first gate driver 240 b is located in thefirst peripheral region, there are fewer OT₂ output terminals than thenumber of gate lines in the first display area (n). Thus, the number ofthe data signal output terminals may be increased to enhance theresolution without necessarily enlarging the driver 230 b. In theparticular embodiment, the first gate driver 240 b is external to thedriver 230 b. However, the invention is not so limited. In FIG. 8A andFIG. 8B, the second gate control signal output terminals (OT₃) aredivided between the second edge region (EP₂) and the fourth edge region(EP₄).

An image is displayed in the second display region DA₂ when the secondgate driving part 234 b applies the second gate signals to the secondgate signal output terminals OT₃₋₁ to OT_(3−i) in response to the secondvertical control signal VCS2. As mentioned above, the second displayregion DA₂ receives its data line signals from the connecting linesCL₁₋₁ to CL_(1−j).

Not shown in FIGS. 5 and 7, the driver chip 230 b may further include aDC/DC converting section and a voltage applying section with a commonvoltage source. The DC/DC converting section receives a voltage andlowers the voltage to a predetermined level for application of thevoltage to the control section 231 b, the data driving section 233 b,the common voltage source, and the first and second gate drivers 240 band 234 b. The common voltage outputs first and second common voltagesthat are applied to the first display region DA₁ and the second displayregion DA₂, respectively.

Embodiment 2

FIG. 9, FIG. 10, FIG. 11, FIG. 12A and FIG. 12B pertain to theelectronic device 600 c including a second embodiment of the driver 230,herein referred to as the driver 230 c. The driver 230 c is similar tothe driver 230 b described above in that it also has three sets ofoutput terminals. However, unlike the driver 230 b, there is no secondgate driver (reference numeral 234 b in FIG. 7) that is integrated intothe driver chip. Instead of the second gate driver that is integratedinto the driver 230 b of Embodiment 1, the driver 230 c uses the secondgate driver 310 c that is located in the second peripheral region fordistributing the gate signals to the second display panel 300 c.

FIG. 9 is a schematic view of the primary and secondary display panels200 c, 300 c that are operated by the driver 230 c. As in the embodimentdescribed above, the primary display panel 200 has first gate linesGL₁₋₁ to GL_(1−n), and first data lines DL₁₋₁ to DL_(1−m). The driver230 c receives signals from the CPU 100 (see FIG. 2) via the firstprinted circuit board 250 and outputs different data line signals forthe first data lines DL₁₋₁ to DL_(1−m). As for the gate lines GL₁₋₁ toGL_(1−n), the driver 230 b forwards the gate line signals to the firstgate driver 240 b, which then distributes the signals to the gate linesGL₁₋₁ to GL_(1−n).

The secondary display panel 300 is also driven by the driver 230 c. Asin Embodiment 1, a subgroup of the first data lines, namely DL₁₋₁ toDL_(1−j), are electrically coupled to the second data lines DL₂₋₁ toDL_(2−j) via the connection lines CL₁₋₁ to CL_(1−j) on the secondprinted circuit board 350. Signals are transmitted from the driver 230 bto the second gate lines GL₂₋₁ to GL_(2−i) in a different manner than inEmbodiment 1. Instead of exiting the driver 230 c as pre-divided gatelines as in Embodiment 1, the signals for the second gate lines aretransmitted via a connecting line CL₂ that runs along the thirdsub-region SA3, across the second printed circuit board 350, and intothe second gate driver 310 b. The second gate driver 310 b is located inthe sixth sub-region SA6. The signals are distributed among the secondconnection lines CL₂₋₁ to CL_(2−i) at the second gate driver 310 c. Thesecond connection lines CL₂₋₁ to CL_(2−i) couple to the signals to therespective second gate lines GL₂₋₁ to GL_(2−i).

As shown in FIG. 10, the second gate driver 310 c is electricallyconnected to the second gate lines GL₂₋₁ to GL_(2−i) for coupling thesecond gate signals to the second gate lines GL₂₋₁ to GL_(2−i) insequence. The second gate driver 310 c includes a shift register having(i+1) number of stages SRC₁ to SRC_(i+1), wherein the stages areelectrically connected to each other. Specifically, an output terminalOUT of a stage is electrically connected to a control terminal CT of aprevious stage and an input terminal IN of a next stage.

The second gate driver 310 c is electrically connected to terminals forreceiving a second start signal ST2, a third clock signal CK2, a fourthclock signal CKB2 having a phase that is inverse to that of the thirdclock signal CK2, a ground voltage Vss and a source voltage V_(DD).

The third clock signal CK2 is applied to odd numbered stages SRC₁, SRC₃,. . . CRC_(n+1) while the fourth clock signal CKB2 is applied to evennumbered stages SRC₂, SRC₄, . . . , SRC_(n). The second start signal ST2is applied to the first and last stages SRC₁ and SRC_(n+1).

When the second start signal ST2 is applied to the first stage SRC₁, thefirst stage SRC₁ outputs the third clock signal CK2 as a first gatesignal. Then, the second stage SRC₂ receives the first gate signal fromthe first stage SRC₁, and the second stage SRC₂ outputs the fourth clockCKB2 as the first gate signal. Thus, i-number of stages SRC₁ to SRC_(i)outputs the first gate signal in sequence.

FIG. 11 is a block diagram of the driver 230 c of FIG. 9. The originaldata signal O-DATA and the original control signal OCS are applied to aninput terminal IN of the driver 230 c. The driver 230 c is arectangular-shaped chip having a first, second, third, and fourth edgeregions EP₁, EP₂, EP₃, and EP₄ that are defined by the four edges of thechip surface. The first and second edge regions EP₁ and EP₂ are nearedges that are substantially parallel to each other, and the third andthe fourth edge regions EP₃ and EP₄ are near edges that aresubstantially parallel to each other. The input terminal IN is formednear the first edge region EP₁ in this embodiment, as shown in FIG. 11.

The control section 231 c provides the memory section 232 c with theoriginal data signal O-DATA, so that the memory section 232 c stores theoriginal data signal O-DATA. Then, the control section 231 c reads thedata signals stored in the memory section 232 c line by line, inresponse to the original control signal OCS. The control section 231 coutputs first and second data signals read from the memory section 232c, a horizontal control signal HCS for driving the data driving section233 c, a first vertical signal VCS1 for controlling the first gatedriver 240 c, and a second vertical control signal VCS2 for controllingthe second gate driver 310.

The data driving section 233 c transmits the first and second datasignals M-DATA and S-DATA to the first data lines DL1-1 to DL1−m via thedata signal output terminals OT₁₋₁ to OT_(1−m) in response to thehorizontal control signal HCS provided from the control section 221 c.The data driving section 233 c transmits the gate signals through thefirst gate driving output terminal OT₂ and the second gate signal outputterminal OT₃. The first vertical control signal VCS1 is output throughthe first gate signal output terminal OT₂ and the second verticalcontrol signal VCS2 is output through the second gate signal outputterminal OT₃.

FIG. 12A is an enlarged view of the portion marked as “C” in FIG. 9, andFIG. 12B is an enlarged view of the portion marked as “D” in FIG. 9. Asshown in FIGS. 12A and 12B, the data signal output terminals OT₁₋₁ toOT_(1−m) are electrically connected to the first data lines DL₁₋₁ toDL_(1−m) of the first display region DA₁ at the first sub-region SA1. Asubgroup of the first data lines DL₁₋₁ to DL_(1−m), namely DL₁₋₁ toDL_(1−j), is electrically connected to the second data lines DL2-1 toDL2−j via the first connection lines CL₁₋₁, to CL_(1−j). Thus, the firstdata signal M-DATA output from the data driving section 223 c is appliedto the first data lines DL₁₋₁ to DL_(1−m). The second data signal S-DATAis applied to the second data lines DL₂₋₁ to DL_(2−j) of the seconddisplay region DA₂ via a subset DL₁₋₁ to DL_(1−j) of the first datalines and the first connection lines C₁₋₁ to C_(1−j).

As shown in FIGS. 12A and 12B, the first gate signal output terminal OT₂is formed at the third edge region DP3 of the driver chip 210, and thesecond gate signal output terminal OT₃ is formed at the fourth edgeregion EP₄.

Referring back to FIGS. 9 and 11, the first gate signal output terminalOT₂ is electrically connected to the first gate driver 240 c at thesecond sub-region SA2, so that the first vertical control signal VCS1 isapplied to the first gate driver 240 c. The first gate driver 240 capplies the first gate signal to the first gate lines GL₁₋₁ to GL_(1−n),in response to the first vertical control signal vcS1.

The second gate signal output terminal OT₃ is electrically connected tothe second gate driver 310 c via the second connection line CL₂ formedon the third sub-region SA3 and the second flexible printed circuitboard 350. Thus, the second vertical control signal VCS2 is applied tothe second gate driver 310 c. The second gate driver 310 c applies thesecond gate signal to the second gate lines GL₂₋₁ to GL_(2−i) inresponse to the second vertical control signal VCS2.

The first and second gate drivers 240 c and 310 c are not built into thedriver 230 c. Thus, the first and second gate signal output terminalsOT₂ and OT₃ output the first and second vertical control signals VCS1and VCS2, respectively. In this embodiment, the third and fourth edgeregions EP₃ and EP₄ are shared by some of the data signal outputterminals OT₁₋₁ to OT_(1−m) and some gate signal output terminals.Through this sharing of edge regions EP₃ and EP₄, the number of the datasignal output terminals OT₁₋₁ to OT_(1−m) can be increased, therebyenhancing the resolution of the primary and/or secondary display panels200 c, 300 c without increasing the size of the driver 230 c.

Embodiment 3

FIG. 13, FIG. 14, FIG. 15A, and FIG. 15B pertain to the electronicdevice 600 d having a third embodiment of the driver chip 230, hereinreferred to as the driver 230 d. This electronic device 600, likeEmbodiment 2, has a first gate driver 240 d and a second gate driver 310d that are external to the driver 230 c. However, unlike Embodiment 2,this embodiment does not include separate first and second gate signaloutput terminals. As will be explained below, both the first and thesecond vertical control signals VCS1 and VCS2 are output from the driver230 d through a shared gate signal output terminal.

FIG. 13 is a schematic view of the primary and secondary display panels200 d, 300 d that are operated by the driver 230 d. As in theembodiments described above, the primary display panel 200 d has firstgate lines GL₁₋₁ to GL_(1−n), and first data lines DL₁₋₁ to DL_(1−m).The driver 230 d receives signals from the CPU 100 (see FIG. 2) via thefirst printed circuit board 250 and outputs different data line signalsfor the first data lines DL₁₋₁ to DL_(1−m). As for the gate lines GL₁₋₁to GL_(1−n), the driver 230 d forwards the gate line signals to thefirst gate driver 240 d, which then distributes the signals to the gatelines GL₁₋₁ to GL_(1−n).

The secondary display panel 300 d is also driven by the driver 230 d. Asin Embodiments 1 and 2, a subgroup of the first data lines, namely DL₁₋₁to DL_(1−j), are electrically coupled to the second data lines DL₂₋₁ toDL_(2−j) via the connection lines CL₁₋₁ to CL_(1−j) on the secondprinted circuit board 350. However, signals are transmitted from thedriver 230 d to the second gate lines GL₂₋₁ to GL_(2−i) in a differentmanner than in Embodiment 1 or Embodiment 2. In this embodiment, thegate control signals for both the first and the second gate lines passthrough the first gate driver 240 d, of which only a subgroup reachesthe second gate driver 310 d. In response to the first gate controlsignals, the first gate driver 240 d applies the first gate signals tothe first gate lines GL₁₋₁ to GL_(1−n). The second gate control signalspass through the first gate driver 240 d, cross over to the seconddisplay panel 300 via the connecting line CL₂, and become applied tosecond gate lines GL₂₋₁ to GL_(2−i) by the second gate driver 310 d. Theconnecting line CL₂ extends across the fourth sub-region SA4, across thesecond printed circuit board 350, and forms an input to the second gatedriver 310 d. The second gate driver 310 d is located in the fifthsub-region SA5.

FIG. 14 is a block diagram of the driver chip 230 d shown in FIG. 13. Asshown, the driver chip 230 d has several components in common with thedriver chip 230 c of Embodiment 2 described above. For example, thedriver chip 230 d has the control section 231 d, the memory section 232d, and a data driving section 233 d. The control section 231 d outputsfirst and second data signals M-DATA and S-DATA, a data control signal(HCS), and the first and second vertical control signals VCS1 and VCS2in response to the original data signal O-DATA and the original controlsignal OCS.

The data driving section 233 d applies the first and second data signalsM-DATA and S-DATA to the data signal output terminals OT₁₋₁ to OT_(1−m)of the driver 230 d in response to the data control signal HCS from thecontrol section 231 d.

Unlike Embodiment 2, which includes the control section 231 c havingseparate gate control signal output terminals OT₂ and OT₃, the controlsection 231 d uses a shared gate signal output terminal OT₂. The driver230 d outputs the first and the second gate control signals (VCS1 andVCS2) through the shared gate signal output terminal OT₂. As shown, theshared gate signal output terminal OT₂ is formed near the third edgeregion EP₃ of the driver 230 d.

The shared gate signal output terminal OT₂ is electrically connected tothe first gate driver 240 d at the second sub-region SA2, so that thefirst vertical control signal VCS1 is applied to the first gate driver240 d. The first gate driver 240 d applies the first gate signal to thefirst gate lines GL₁₋₁ to GL_(1−n), in response to the first verticalcontrol signal VCS1.

The first gate driver 240 is electrically connected to the second gatedriver 310 via the second connection line CL₂. Thus, the second verticalcontrol signal VCS2 is applied to the second gate driver 310 d via thefirst gate driver 240 d and the second connection line CL₂. The secondgate driver 240 d and the second connection line CL₂. The second gatedriver 310 d applies the second gate signal to the second gate linesGL₂₋₁ to GL_(2−i), in response to the second vertical control signalVCS2.

FIG. 15A is an enlarged view of the portion marked “E” in FIG. 13, andFIG. 15B is an enlarged view of the portion marked as “F” in FIG. 13. Asshown, the data signal output terminals OT₁₋₁ to OT_(1−m) occupy threedifferent edge regions of the driver 230 d. More precisely, the datasignal output terminals OT₁₋₁ to OT_(1−m) are located on the second,third, and fourth edge regions EP₂, EP₃, and EP₄, wherein the third edgeregion EP₃ is shared with the gate control signal output terminal OT₂.By consolidating the gate control signals into one set of outputterminals OT₂, the number of the data signal output terminals OT₁₋₁ toOT_(1−m) may be increased to enhance the resolution. Since the totalnumber of output terminals remain the same, enhanced resolution isachieved without enlarging the overall size of the driver 230 d.

In the embodiments described above, the driver chip 230 is used to driveboth the primary and the secondary LCD panels 200, 300. In theembodiments described, there is one data driving section that is builtinto the driver chip 230. Since the data driving section sends datasignals to different data lines, the data driving section beingintegrated into the driver 230 results in many of the output terminalsof the driver chip 230 being coupled to data lines. As for the gatedrivers, there is a first gate driver for the primary display panel 200and a second gate driver for the secondary display panel 300. The gatedrivers may be formed in the display panels. Alternatively, as shownabove in FIG. 7, the second gate driver may be implemented as anintegral part of the driver chip 230. Where the gate driver is externalto the driver 230, the second gate control signals may reach the secondgate driver through the first gate driver for the primary display panel200. Alternatively, the second gate signals may reach the second gatedriver via a connecting line that does not include the first gatedriver.

It is well known that the gate drivers scan the display panels 200, 300line by line. The first and second gate control signals (VCS1 and VCS2)may send control signals to the gate drivers 240 and 310 so that the twogate drivers scan the respective gate lines at the same time.Alternatively, the first and second gate control signals (VCS1 and VCS2)may send control signals so that the second gate driver 310 starts itsscanning after a preselected line of the first gate driver 240 isscanned.

The invention has been described using variations and examples to enableone skilled in the art to develop an understanding of the invention.Numerous variations may be implemented within the spirit and scope ofthe invention. As such, one skilled in the art should reference theclaims of the invention rather than the foregoing examples to assessrights entitled to with respect to the claims.

What is claimed is:
 1. An electronic device comprising: a first displayarea having a plurality of first gate lines and a plurality of firstdata lines; a first peripheral region adjacent to the first displayarea; a second display area having a plurality of second gate lines anda plurality of second data lines, wherein the second data lines areelectrically coupled to the first data lines; a second peripheral regionadjacent to the second display area; a driver chip configured to outputsgate control signals and provides data signals to the data lines,wherein the driver chip includes an internal gate driver configured tosend gate signals to the second gate lines; and an external gate driveroutside of the driver chip and positioned in the first peripheralregion, wherein the external gate driver is configured to provide firstgate signals to the first gate lines in response to the gate controlsignals.
 2. The device of claim 1, wherein the driver chip comprises: aninput terminal for receiving an input data signal and an input controlsignal; a control section coupled to the input terminal for generating adata control signal (HCS), a first gate control signal (VCS1), and asecond gate control signal (VCS2) in response to the input data signaland the input control signal, wherein the second gate control signal isforwarded to the internal gate driver and the second gate control signalis forwarded to the external gate driver; and data signal outputterminals for supplying the data signals to the data lines.
 3. Thedevice of claim 1, wherein the external gate driver includes amorphoussilicon thin film transistors.